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June 14, 2017      

Hard and repetitive work weakens the body. The consequences are chronic back pain and other ailments that keep workers off the job, resulting in high costs. Collaborative robot arms are changing this situation. The robot holds the tool, and the worker simply has to guide it — like a partner in a dance.

Every fourth employee in Europe suffers from severe back pain. Musculoskeletal disorders are among the most common work-related illnesses. The reasons are simple: high-paced work, monotonous procedures, and heavy loads. The consequences are severe. Not only does the health of the individual suffer, but the economic and social costs are also immense.

To combat this societal problem, new solutions are needed. One of these is the Cobot 7A-15, created by French company RB3D. Cobot takes a load off the industrial worker’s back — literally. The robot arm, which is mounted to a wall, is equipped with seven axes and has an action radius of more than 2 m (6 ft.).

A heavy tool such as a grinder can be attached to the lower end of the robot arm. This means that the workers no longer need to carry the weight of the device themselves but instead only guide it. Cobot 7A-15 takes care of the heavy lifting.

Sensors transmit the desired movements

The robot assists the operators in executing the movements that they would like to perform, whether up, down, left, or right. A sensor immediately recognizes the operator’s intent. The controller then ensures that the robot arm goes where it should, without exertion on the part of the worker. The quick, smooth movements of the arm are executed by maxon DC motors of the RE series. These are used on all of Cobot 7A?15’s axes.

Maxon motors arm

All axes of this robot arm are equipped with motors and control elements of maxon motor. Image ©RB3D

The high-precision brushed motors, with 150 W and 250 W of power, amplify the force exerted by the worker many times over. The worker saves energy and can concentrate on the work itself.

“If a certain task would usually require 20 kg of force, the Cobot reduces the force needed to 1 kg,” said Serge Grygorowicz, CEO and founder of RB3D.

Grygorowicz and his team want to improve work conditions in the industrial sector and thus reduce musculoskeletal disorders.

Cobot 7A-15 relies on maxon drives

Grygorowicz said that maxon drives were his team’s first choice. “They provide the best combination of weight, quality and power density,” he said.

The requirements that the motors have to meet are high. They have to provide both speed and torque and have to transmit large forces with high precision yet remain easy to control.

Maxon motor

Maxon DC motors are fitted with powerful permanent magnets, and the “heart” of the motor is a patented ironless rotor.

Not only did maxon motor supply the motors, but it also provided also the entire drive system. The DC motors of the RE series are used in combination with the matching planetary gearheads, encoders, and EPOS positioning motor controllers.

There were several key factors that contributed to the French developer’s decision to work with maxon: the compactness, torque, and acceleration of the solution, as well as having all parts of the system come from a single source.

Know-how from the nuclear industry

In designing its drives, maxon worked closely with CEA LIST, a French research institute which played an important role in the development of the Cobot 7A-15.

Until recently, there were hardly any industrial robots that could be controlled and guided by means of a human’s strength. Those that did exist were slow and did not significantly reduce the amount of effort required from the worker.

This made the experience that CEA LIST has gained with force feedback controllers in the nuclear industry even more valuable. With this specialized knowledge, RB3D succeeded in developing a new generation of industrial robots that could permanently change the work conditions in workshops.

Editor’s note: This article is a special sponsored submission by maxon motor ag and appears in driven: The maxon motor magazine.

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